page_title: Landing Craft Assault
section_title: Production and development history
hierarchical_section_title: Landing Craft Assault / Production and development history
caption_attribution_description: English: http://www.history.navy.mil/photos/images/ac00001/ac01087c.htm Photo #: USA C-1087 (Color) British Navy Landing Craft LCA-1377 Carries American troops to a ship, in a British port during preparations for the Normandy invasion, circa May-June 1944. Note British Sailors in the boat's conning station. Letters "PB" on the boat's side indicate that it is assigned to HMS Prince Baudouin.
context_page_description: Landing Craft Assault was a landing craft used extensively in World War II. Its primary purpose was to ferry troops from transport ships to attack enemy-held shores. The craft derived from a prototype designed by John I. Thornycroft Ltd. of Woolston, Hampshire, UK. During the war it was manufactured throughout the United Kingdom in places as various as small boatyards and furniture manufacturers.
  Typically constructed of hardwood planking and selectively clad with armour plate, this shallow-draft, barge-like boat with a crew of four could ferry an infantry platoon of 31, with space to spare for five additional specialist troops, to shore at 7 knots. Men generally entered the boat by walking over a gangplank from the boat deck of a troop transport as the LCA hung from its davits. When loaded, the LCA was lowered into the water. Soldiers exited by the boat's bow ramp.
  The LCA was the most common British and Commonwealth landing craft of World War II, and the humblest vessel admitted to the books of the Royal Navy on D-Day.
context_section_description: With few exceptions, the hull, ramp, and power plant of the LCA remained the same throughout the war. Early on the coxswain's position was moved from aft to forward on the starboard side. Other particulars could vary greatly; some LCAs having Direction finding antenna loops, others Danforth anchors on vertical racks forward. The hatch layout on the stern deck varied, as did the placement and type of mooring bits, chocks, cleats, fairleads, and fuel caps. Photographic evidence shows all these variations and also differences in the placement of the lifelines that were looped along either hullside for men in the water.
  The Admiralty ordered 18 LCAs from Messrs. Thornycroft in April 1939. These early boats weighed more than 9 tons and had flush-decked hulls, an armoured bulkhead forward that wrapped around the steering compartment on the starboard side. The steering compartment's armour plates stood about two feet proud of the deck line. In September, 8 more were ordered. Ford V8 marine conversions by Thornycroft powered the early groups of LCAs, these water-cooled petrol engines developing 65 hp each when driving the 19"x14" 2-bladed propellers through a 41:20 gear reduction. The twin propulsion units gave a speed of 10½ knots at 2,800 revolutions per minute with a load of 8,300 lb (3,800 kg) in the boat. Later craft used propellers with three blades.
  The Admiralty placed orders for 30 LCAs in March 1940. By this time, Thornycroft were subcontracting with South Coast yacht-builders to fill the Admiralty's many small boat orders as Thornycroft yards were overtaxed building war-emergency convoy escorts and the like. Some LCAs - Numbers 24-29 and 51 - were fitted with Parsons conversions of the Ford V8, driving propellers similar to the standard type but on a 2:1 gear reduction; these LCAs did 12 knots (22 km/h) at 3,300 revolutions. The standard engine fitted in almost all other craft was the Scripps conversion of the Ford V8. Official trial results for craft built in 1940-1 with this engine show a consistent performance with an unladen speed of 11 knots (20 km/h) at 2,800 revolutions. June saw 64 more LCA orders, and then between late September and March 1941 another 104. These early craft did not yet have the later standard portside armoured Lewis gun position, but nevertheless, had framed canvas hold covers, scaling ladders mounted on the decks amidships, and various other refinements dropped when mass production got into full swing. The finish and performance of these early LCAs were quite fine, which might be expected as these boats were built in established Thornycroft selected yards, but in circumstances of nightly blackouts, air raids, wartime restrictions, and shortages the LCA building programme was a remarkable achievement.
  About April 1941 the Admiralty decided not to place orders exclusively through Thornycroft and leaving them to sub-contract, rather, the Admiralty placed orders directly with cabinet makers, carpenters, and yacht-builders in all parts of Britain. After February 1942, LCAs began being manufactured with deck armour in addition to their vertical armour. In the 42 months prior to the end of 1944 Britain was able to produce an additional 1,694 LCAs. Certain details were modified as production ran, but the basic LCA design remained unchanged for the length of the war. By the time production was in full tilt in preparation for Operation Overlord production rose to sixty LCAs a month.
  Sources differ regarding the speed and endurance of the LCA. By 1945 the all-up loaded weight of an LCA had risen to 13½ tons, due to the addition of further armour and the weight of weaponry an infantry platoon expected to carry into battle. As with all wooden vessels after prolonged immersion, weight increased in the LCA and performance consequently fell. The equipment had evolved and so had the personnel. The time of needing a few craft for raiding was past and the time for invasion, for scores of flotillas dawned. Another obstacle to getting the best performance out of the LCA was the early war tendency to return ratin
caption: Royal Navy Landing Craft LCA-1377 carries American troops to a ship in a British port, during preparations for the Normandy invasion, circa May–June 1944.
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